Today we will talk about OMEGA 3, which are VERY important nutrients for the body that seem to have REAL and PROPER HEALTH functions against certain disorders of METABOLISM
So first of all, WHAT ARE OMEGA 3s?
Omega 3 are molecules that belong to the nutritional group of LIPIDS. In particular, these are FATTY ACIDS, or CARBON CHAINS which, through an ESTERIFICATION bond, bind to an alcohol to structure more ARTICULATED molecules. These, if composed ONLY of 1, 2 or 3 fatty acids, are called MONO-, DI- or TRIGLYCERIDES respectively, and belong to the group of SIMPLE LIPIDS; on the other hand, if in addition to ALCOHOL there are OTHER substances (such as phosphoric acid, nitrogenous bases or carbohydrates), they acquire the title of COMPLEX LIPIDS. It is therefore logical to deduce that, being part of both simple and complex lipids, fatty acids represent a very important "SLICE" of the lipids present in NATURE and therefore also in FOOD. The abundance of fatty acids in living tissues is ESPECIALLY attributable to ONE of the various BIOLOGICAL functions that they cover, namely the CALORIC one. For example, from 1g of lipids, the human metabolism is able to obtain about 9kcal and, not surprisingly, the triglycerides make up our largest energy reserve, that is the ADIPOSE TISSUE.
However, fatty acids are NOT all the same! They differ mainly in the length of the carbon chain and in the nature of the bonds that characterize them. Obviously, the various discrepancies are NOT RANDOM and each type of fatty acid has CHEMICAL, PHYSICAL and METABOLIC IMPACT on the body quite different from each other.
That said, let's try to better understand WHAT KIND OF FATTY ACIDS OMEGA 3 ARE!
First of all, omega 3 (as ALSO omega 6) are called ESSENTIAL FATTY ACIDS, as the body is NOT able to produce them independently. In reality, of all the omega 3 and omega 6, the PROPERLY ESSENTIAL ones are the ALPHA-LINOLENIC acid (an omega 3) and the LINOLEIC ACID (an omega 6), from which the body is also able to obtain the others! However, to SIMPLIFY the topic, we will now enclose them all in the group of essentials.
Omega 3 are LONG CHAIN POLYUNSATURATED lipids; they have AT LEAST 2 DOUBLE BONDS between the carbon atoms of the chain which is NEVER shorter than 13 units. This feature, which makes them LIQUID even at low temperatures BUT absolutely UNSTABLE to LIGHT, HEAT and OXYGEN, also hides a VERY IMPORTANT METABOLIC function that we will see later.
Before describing more accurately the omega 3 fatty acids, I think it is quite important to clarify their affinities and differences with OMEGA 6. It is true that they are ALL polyunsaturated fatty acids, both of the ESSENTIAL type, and represent the precursors of different types of EICOSANOIDS (ie molecules responsible for the balance of INFLAMMATION); on the other hand, they stand out CONSIDERABLY for three very specific reasons. The first is of a chemical nature: as the name suggests, in omega 3s, the last double bond is placed on the third carbon (counting it from the end of the chain), while omega 6s have it on the sixth. The second reason is metabolic: while omega 3 play an ANTI-inflammatory role, omega 6 ALSO support the synthesis of pro-inflammatory EICOSANOIDS. Finally, the third reason is nutritional: while omega 3s are LITTLE present in the foods of the Western diet, omega 6s seem PROPORTIONALLY in excess compared to the previous ones.
Now let's see in more detail WHAT are the omega 3 fatty acids.
The molecules belonging to this group are 3, namely: ALPHA-LINOLENIC ACID, EICOSAPENTAENOIC ACID (or EPA) and DOCOSAESAENOIC ACID (or DHA).
ALPHA-LIOLENIC ACID has the formula 18: 3, which means that it has a chain 18 atoms long, in which 3 double bonds are distributed in CIS conformation; these are placed respectively in position 9, 12 and 15. The EPA has formula 20: 5 and the double bonds are located in position 5, 8, 11, 14 and 17. Finally, the DHA has formula 20: 6, with double bonds undermined in positions 4, 7, 10, 13, 16 and 19.
Obviously, although of great scientific importance, these are technical details that are of little interest to most listeners; what must be CLEAR instead, is the set of their FUNCTIONS, their RECOMMENDED RATION and the FOOD SOURCES that contain them.
So, let's proceed in order and start with their DUTIES in the body.
Like all fatty acids, omega 3s can also enter cells and be oxidized for energy production. They provide 9kcal / g and, if synthesized again in triglycerides within the adipocytes, make up the adipose tissue and constitute a reserve source of the body.
Omega 3 also have an important structural function. Constituting the phospholipids contained in the famous "liquid mosaic" typical of cell membranes, these are responsible for their fluidity.
It has already been anticipated that essential fatty acids are the precursors of EICOSANOIDS, and that, while omega 3s favor the synthesis of ANTI-inflammatory ones, omega 6s also seem to support the production of PRO-inflammatories. Of course, this doesn't mean that omega 6s are harmful! All eicosanoids are very important, BUT it is also necessary that they remain in balance with each other. In practice, the risk of an excess of omega 6 ... or of a deficiency of omega 3 ... would be to shift the "balance" in favor of systemic inflammation with the risk of promoting the related complications.
Furthermore, the "GOOD" eicosanoids produced by omega 3 are also responsible for a LOWER PLATE AGGREGATION and play a very important ANTI-thrombotic role.
As if that weren't enough, omega 3s also have a very significant metabolic impact. They act on LIPEMIA by significantly decreasing TRIGLYCERIDES and (albeit less effectively) reducing total CHOLESTEROL, as well as increasing the good HDL. The omega 3s therefore have a marked ANTI-atherogenic function.
Last but not least, omega 3 have a positive effect on blood pressure REDUCING the arterial pressure, known as the Hypotensive function.
Well, for those who do not know, the combination of the functions: ANTI-INFLAMMATORY, ANTITROMBOTIC, ANTIATEROGENIC and HYPOTENSIVE, constitutes a very effective preventive and therapeutic system in the fight against CEREBROUS and CARDIO-VASCULAR PATHOLOGIES.
Other HYPOTHETICAL functions (far from negligible, but less evident than those already described) are: protection from the onset of type 2 diabetes mellitus, and the protection or delay of the onset of Alzheimer's neurodegenerative disease.
That said, let's now move on to the RECOMMENDED RATION of omega 3!
As anticipated, omega 3 are essential and therefore must necessarily be introduced with the diet.
Their deficiency is difficult to assess, as it DOES NOT manifest itself with TYPICAL or EXCLUSIVE clinical symptoms or signs, although it could contribute to the onset of certain metabolic diseases.
On the other hand, the INDISCRIMINATE excess of POLYUNSATURATED FATS (including omega 3) can cause: the formation of potentially toxic LIPO-PEROXIDES, an increased BLOODING speed and the alteration of the IMMUNE function.
The most effective system to monitor the fitness of ESSENTIAL FATS (omega 3 and omega 6) in the diet is the MEAD Index, or the RATIO between EICOSATRIENOIC acid and ARACHIDONIC acid, within the PHOSPHOLIPIDS contained in the serum. some blood. When the value exceeds the 0.4 threshold, the condition is considered pathological!
Compared to that of adults, the need for omega 3 is greater in special conditions such as in young children, pregnant women, nurses and the elderly. However, respecting what is mentioned in the Recommended Nutrient Intake Levels for the Italian population, omega 3 must be provided in PERCENTAGE to the daily calories and, more precisely, between 0.2 and 0.5% of the total. In this way, the intake of fatty acids increases proportionally to the overall nutritional needs of the body (taking care to prefer 0.5 instead of 0.2 in the special physiological conditions mentioned above).
But, ultimately, WHERE are these omega 3s found?
Dietary sources of omega 3 are animal and vegetable.
Alpha-linolenic acid is the omega 3 most present in plant products, in particular in oil seeds, in their oils, but also in green leafy vegetables. Some examples of RAW foods rich in this omega 3 are: soy, flax seeds, hemp seeds and walnuts; as far as the oils are concerned, the most concentrated are: kiwi seed oil, linseed oil, hemp oil, rapeseed oil, walnut oil and soybean oil.
On the other hand, EPA and DHA, which are BIOLOGICALLY MUCH MORE ACTIVE, are more present in foods of animal origin and, in particular, in fishery products such as: blue fish (therefore tuna belly, bonito, mackerel , sardines, amberjack, etc.), liver of these animals and krill. Obviously, the foods richest in EPA and DHA are made from animal oils obtained from the liver of fish and from krill; however, another VEGETABLE food has recently been discovered, but still MARINE, even more concentrated in EPA and DHA than those just described, namely ALGAE, from which it is also possible to extract the oil.
We conclude the movie by recalling once again that omega 3 fatty acids are NOT resistant to light, heat and oxygen exposure. This means that oils rich in omega 3 are NOT suitable for preservation in oil and cooking. Furthermore, it is always recommended to keep them in the refrigerator, in the dark and well sealed.
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